diff --git a/poetry.lock b/poetry.lock
index 28383a5..3fcab4b 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -1,47 +1,68 @@
 [[package]]
-category = "dev"
-description = "Code coverage measurement for Python"
 name = "coverage"
+version = "5.3.1"
+description = "Code coverage measurement for Python"
+category = "dev"
 optional = false
 python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*, <4"
-version = "5.0b1"
 
 [package.extras]
 toml = ["toml"]
 
 [metadata]
-content-hash = "1e7f4729aa212c1e9953755a06bef5e7c8373a19ebb7fa020147a045639cb196"
+lock-version = "1.1"
 python-versions = "^3.7"
+content-hash = "891cf807ed402900a4c0c8c9507c48c92c33cb2e9ab96adad08154e18ab1f295"
 
 [metadata.files]
 coverage = [
-    {file = "coverage-5.0b1-cp27-cp27m-macosx_10_12_x86_64.whl", hash = "sha256:8210a6f93c4a8c6d460b402e20e38399529b99200c3318542faf6a520c9b6a5c"},
-    {file = "coverage-5.0b1-cp27-cp27m-macosx_10_13_intel.whl", hash = "sha256:2358e685d0253125da42a48396038d4c7b4cd1448c00bbc4bda0cb8c43c2a870"},
-    {file = "coverage-5.0b1-cp27-cp27m-manylinux1_i686.whl", hash = "sha256:5ffb39624bc573177888a21fb301ccee46838c600b27d58c3e9dae495f44d34a"},
-    {file = "coverage-5.0b1-cp27-cp27m-manylinux1_x86_64.whl", hash = "sha256:79ef4a2bb862110bd585174e551a783bee5c3aa461734a2ac7429193be357589"},
-    {file = "coverage-5.0b1-cp27-cp27m-win32.whl", hash = "sha256:50cf23523ab3a724c6905d3b60f87fa8250d9bae3995e09f49f63effa2b54f15"},
-    {file = "coverage-5.0b1-cp27-cp27m-win_amd64.whl", hash = "sha256:f7162f2e3711f3a08a8a741f92e1f63afd58d0713177979f2cf9723dd50161cf"},
-    {file = "coverage-5.0b1-cp27-cp27mu-manylinux1_i686.whl", hash = "sha256:699b3072b7f0e69ed175a88fa8b2ec7eefc4f34d490c54ed9a52feff21a15fdc"},
-    {file = "coverage-5.0b1-cp27-cp27mu-manylinux1_x86_64.whl", hash = "sha256:aedad67c30326a1af324f45833a40b97180664912deb29942459ddbe9fa0ce19"},
-    {file = "coverage-5.0b1-cp35-cp35m-macosx_10_12_x86_64.whl", hash = "sha256:25017cf384eeed2e6caf72efd3ec4124e32a8b7a4387600499104387975400c7"},
-    {file = "coverage-5.0b1-cp35-cp35m-manylinux1_i686.whl", hash = "sha256:54c84a68abd8c4c5b71878b35eb85321df41f3d144c78181867d5b026ec74994"},
-    {file = "coverage-5.0b1-cp35-cp35m-manylinux1_x86_64.whl", hash = "sha256:c0df57e189dacd2606cae6386acf127d01d85b2bf49acd9a65543b5d6c359ddc"},
-    {file = "coverage-5.0b1-cp35-cp35m-win32.whl", hash = "sha256:2e2de9423ff8b14303a97eafddd16c479fbcc9a0b8b0be3b7c3843a3e0cf6d69"},
-    {file = "coverage-5.0b1-cp35-cp35m-win_amd64.whl", hash = "sha256:97ac79ff28f2cda6ac00a803ee582b965951755f61ab43377482bfba450b619a"},
-    {file = "coverage-5.0b1-cp36-cp36m-macosx_10_13_x86_64.whl", hash = "sha256:5b59d661ee7f3200aedd7b71882b7927ea7ed522df75e3853f316a79ad872a2e"},
-    {file = "coverage-5.0b1-cp36-cp36m-manylinux1_i686.whl", hash = "sha256:a5b6395d5957d638f8b1870561607e3c39b1a236ea6cff9eafe5b9bb1db913f2"},
-    {file = "coverage-5.0b1-cp36-cp36m-manylinux1_x86_64.whl", hash = "sha256:324ed908e4e40a6e2451056fe502470ad4e79495cb7a03ecab94e6309c3e117e"},
-    {file = "coverage-5.0b1-cp36-cp36m-win32.whl", hash = "sha256:8d30c10cfd0a6fdf0a2d5023de00ef7b329cd6ead2310c9e53eab79c209acb70"},
-    {file = "coverage-5.0b1-cp36-cp36m-win_amd64.whl", hash = "sha256:e9128444c83bc260aea988bf1ca6278a33ba730955bf94720468c656b61353eb"},
-    {file = "coverage-5.0b1-cp37-cp37m-macosx_10_13_x86_64.whl", hash = "sha256:b077cd0e70f41366ac1f9d09275258fa1906758a5d4f31cacc18b10dfcf90784"},
-    {file = "coverage-5.0b1-cp37-cp37m-manylinux1_i686.whl", hash = "sha256:ad67f0cfdfecbd49b9da46a7e488e6dc32a69388740b85c36a4ef4b33082cbad"},
-    {file = "coverage-5.0b1-cp37-cp37m-manylinux1_x86_64.whl", hash = "sha256:ab32c5fad6905986a7e34e3acf01180a69bb60c2aa7331815b46e51c776a1943"},
-    {file = "coverage-5.0b1-cp37-cp37m-win32.whl", hash = "sha256:e10593c60c5f0bfd8b241bf9f27ef2191a3005b73dde8ada0424f642543a1e59"},
-    {file = "coverage-5.0b1-cp37-cp37m-win_amd64.whl", hash = "sha256:9fe4aacacff9028ed167db108bf013510654f148d83c4857fed61d2ce0588bf2"},
-    {file = "coverage-5.0b1-cp38-cp38-macosx_10_13_x86_64.whl", hash = "sha256:bf572722326ce6704e863447a070039a827072b7179352570859be899b9e6551"},
-    {file = "coverage-5.0b1-cp38-cp38-manylinux1_i686.whl", hash = "sha256:34f865a0cf6255b694a46e4383a7131c61ea72c5b4c4f81d20e522fb1e440b4b"},
-    {file = "coverage-5.0b1-cp38-cp38-manylinux1_x86_64.whl", hash = "sha256:3a2bcc464b60a18f1f7167b95b2773ede93bf3722bfa59e0802717f652b6cc25"},
-    {file = "coverage-5.0b1-cp38-cp38m-win32.whl", hash = "sha256:48d70865266d649b6602e2ba94820d7972ef470d3b72a8fd41a3d17321feed3a"},
-    {file = "coverage-5.0b1-cp38-cp38m-win_amd64.whl", hash = "sha256:b8ea210810d3c14aec7561f8fe0d3eec582d1088100aaa0bb8153d53d867d20f"},
-    {file = "coverage-5.0b1.tar.gz", hash = "sha256:d523e75f2a8a0b4a6a8be1287c0e0e3a561b8832b05ddd987d4cd7c62f3ad3bc"},
+    {file = "coverage-5.3.1-cp27-cp27m-macosx_10_9_x86_64.whl", hash = "sha256:fabeeb121735d47d8eab8671b6b031ce08514c86b7ad8f7d5490a7b6dcd6267d"},
+    {file = "coverage-5.3.1-cp27-cp27m-manylinux1_i686.whl", hash = "sha256:7e4d159021c2029b958b2363abec4a11db0ce8cd43abb0d9ce44284cb97217e7"},
+    {file = "coverage-5.3.1-cp27-cp27m-manylinux1_x86_64.whl", hash = "sha256:378ac77af41350a8c6b8801a66021b52da8a05fd77e578b7380e876c0ce4f528"},
+    {file = "coverage-5.3.1-cp27-cp27m-manylinux2010_i686.whl", hash = "sha256:e448f56cfeae7b1b3b5bcd99bb377cde7c4eb1970a525c770720a352bc4c8044"},
+    {file = "coverage-5.3.1-cp27-cp27m-manylinux2010_x86_64.whl", hash = "sha256:cc44e3545d908ecf3e5773266c487ad1877be718d9dc65fc7eb6e7d14960985b"},
+    {file = "coverage-5.3.1-cp27-cp27m-win32.whl", hash = "sha256:08b3ba72bd981531fd557f67beee376d6700fba183b167857038997ba30dd297"},
+    {file = "coverage-5.3.1-cp27-cp27m-win_amd64.whl", hash = "sha256:8dacc4073c359f40fcf73aede8428c35f84639baad7e1b46fce5ab7a8a7be4bb"},
+    {file = "coverage-5.3.1-cp27-cp27mu-manylinux1_i686.whl", hash = "sha256:ee2f1d1c223c3d2c24e3afbb2dd38be3f03b1a8d6a83ee3d9eb8c36a52bee899"},
+    {file = "coverage-5.3.1-cp27-cp27mu-manylinux1_x86_64.whl", hash = "sha256:9a9d4ff06804920388aab69c5ea8a77525cf165356db70131616acd269e19b36"},
+    {file = "coverage-5.3.1-cp27-cp27mu-manylinux2010_i686.whl", hash = "sha256:782a5c7df9f91979a7a21792e09b34a658058896628217ae6362088b123c8500"},
+    {file = "coverage-5.3.1-cp27-cp27mu-manylinux2010_x86_64.whl", hash = "sha256:fda29412a66099af6d6de0baa6bd7c52674de177ec2ad2630ca264142d69c6c7"},
+    {file = "coverage-5.3.1-cp35-cp35m-macosx_10_9_x86_64.whl", hash = "sha256:f2c6888eada180814b8583c3e793f3f343a692fc802546eed45f40a001b1169f"},
+    {file = "coverage-5.3.1-cp35-cp35m-manylinux1_i686.whl", hash = "sha256:8f33d1156241c43755137288dea619105477961cfa7e47f48dbf96bc2c30720b"},
+    {file = "coverage-5.3.1-cp35-cp35m-manylinux1_x86_64.whl", hash = "sha256:b239711e774c8eb910e9b1ac719f02f5ae4bf35fa0420f438cdc3a7e4e7dd6ec"},
+    {file = "coverage-5.3.1-cp35-cp35m-manylinux2010_i686.whl", hash = "sha256:f54de00baf200b4539a5a092a759f000b5f45fd226d6d25a76b0dff71177a714"},
+    {file = "coverage-5.3.1-cp35-cp35m-manylinux2010_x86_64.whl", hash = "sha256:be0416074d7f253865bb67630cf7210cbc14eb05f4099cc0f82430135aaa7a3b"},
+    {file = "coverage-5.3.1-cp35-cp35m-win32.whl", hash = "sha256:c46643970dff9f5c976c6512fd35768c4a3819f01f61169d8cdac3f9290903b7"},
+    {file = "coverage-5.3.1-cp35-cp35m-win_amd64.whl", hash = "sha256:9a4f66259bdd6964d8cf26142733c81fb562252db74ea367d9beb4f815478e72"},
+    {file = "coverage-5.3.1-cp36-cp36m-macosx_10_9_x86_64.whl", hash = "sha256:c6e5174f8ca585755988bc278c8bb5d02d9dc2e971591ef4a1baabdf2d99589b"},
+    {file = "coverage-5.3.1-cp36-cp36m-manylinux1_i686.whl", hash = "sha256:3911c2ef96e5ddc748a3c8b4702c61986628bb719b8378bf1e4a6184bbd48fe4"},
+    {file = "coverage-5.3.1-cp36-cp36m-manylinux1_x86_64.whl", hash = "sha256:c5ec71fd4a43b6d84ddb88c1df94572479d9a26ef3f150cef3dacefecf888105"},
+    {file = "coverage-5.3.1-cp36-cp36m-manylinux2010_i686.whl", hash = "sha256:f51dbba78d68a44e99d484ca8c8f604f17e957c1ca09c3ebc2c7e3bbd9ba0448"},
+    {file = "coverage-5.3.1-cp36-cp36m-manylinux2010_x86_64.whl", hash = "sha256:a2070c5affdb3a5e751f24208c5c4f3d5f008fa04d28731416e023c93b275277"},
+    {file = "coverage-5.3.1-cp36-cp36m-win32.whl", hash = "sha256:535dc1e6e68fad5355f9984d5637c33badbdc987b0c0d303ee95a6c979c9516f"},
+    {file = "coverage-5.3.1-cp36-cp36m-win_amd64.whl", hash = "sha256:a4857f7e2bc6921dbd487c5c88b84f5633de3e7d416c4dc0bb70256775551a6c"},
+    {file = "coverage-5.3.1-cp37-cp37m-macosx_10_9_x86_64.whl", hash = "sha256:fac3c432851038b3e6afe086f777732bcf7f6ebbfd90951fa04ee53db6d0bcdd"},
+    {file = "coverage-5.3.1-cp37-cp37m-manylinux1_i686.whl", hash = "sha256:cd556c79ad665faeae28020a0ab3bda6cd47d94bec48e36970719b0b86e4dcf4"},
+    {file = "coverage-5.3.1-cp37-cp37m-manylinux1_x86_64.whl", hash = "sha256:a66ca3bdf21c653e47f726ca57f46ba7fc1f260ad99ba783acc3e58e3ebdb9ff"},
+    {file = "coverage-5.3.1-cp37-cp37m-manylinux2010_i686.whl", hash = "sha256:ab110c48bc3d97b4d19af41865e14531f300b482da21783fdaacd159251890e8"},
+    {file = "coverage-5.3.1-cp37-cp37m-manylinux2010_x86_64.whl", hash = "sha256:e52d3d95df81c8f6b2a1685aabffadf2d2d9ad97203a40f8d61e51b70f191e4e"},
+    {file = "coverage-5.3.1-cp37-cp37m-win32.whl", hash = "sha256:fa10fee7e32213f5c7b0d6428ea92e3a3fdd6d725590238a3f92c0de1c78b9d2"},
+    {file = "coverage-5.3.1-cp37-cp37m-win_amd64.whl", hash = "sha256:ce6f3a147b4b1a8b09aae48517ae91139b1b010c5f36423fa2b866a8b23df879"},
+    {file = "coverage-5.3.1-cp38-cp38-macosx_10_9_x86_64.whl", hash = "sha256:93a280c9eb736a0dcca19296f3c30c720cb41a71b1f9e617f341f0a8e791a69b"},
+    {file = "coverage-5.3.1-cp38-cp38-manylinux1_i686.whl", hash = "sha256:3102bb2c206700a7d28181dbe04d66b30780cde1d1c02c5f3c165cf3d2489497"},
+    {file = "coverage-5.3.1-cp38-cp38-manylinux1_x86_64.whl", hash = "sha256:8ffd4b204d7de77b5dd558cdff986a8274796a1e57813ed005b33fd97e29f059"},
+    {file = "coverage-5.3.1-cp38-cp38-manylinux2010_i686.whl", hash = "sha256:a607ae05b6c96057ba86c811d9c43423f35e03874ffb03fbdcd45e0637e8b631"},
+    {file = "coverage-5.3.1-cp38-cp38-manylinux2010_x86_64.whl", hash = "sha256:3a3c3f8863255f3c31db3889f8055989527173ef6192a283eb6f4db3c579d830"},
+    {file = "coverage-5.3.1-cp38-cp38-win32.whl", hash = "sha256:ff1330e8bc996570221b450e2d539134baa9465f5cb98aff0e0f73f34172e0ae"},
+    {file = "coverage-5.3.1-cp38-cp38-win_amd64.whl", hash = "sha256:3498b27d8236057def41de3585f317abae235dd3a11d33e01736ffedb2ef8606"},
+    {file = "coverage-5.3.1-cp39-cp39-macosx_10_9_x86_64.whl", hash = "sha256:ceb499d2b3d1d7b7ba23abe8bf26df5f06ba8c71127f188333dddcf356b4b63f"},
+    {file = "coverage-5.3.1-cp39-cp39-manylinux1_i686.whl", hash = "sha256:3b14b1da110ea50c8bcbadc3b82c3933974dbeea1832e814aab93ca1163cd4c1"},
+    {file = "coverage-5.3.1-cp39-cp39-manylinux1_x86_64.whl", hash = "sha256:76b2775dda7e78680d688daabcb485dc87cf5e3184a0b3e012e1d40e38527cc8"},
+    {file = "coverage-5.3.1-cp39-cp39-manylinux2010_i686.whl", hash = "sha256:cef06fb382557f66d81d804230c11ab292d94b840b3cb7bf4450778377b592f4"},
+    {file = "coverage-5.3.1-cp39-cp39-manylinux2010_x86_64.whl", hash = "sha256:6f61319e33222591f885c598e3e24f6a4be3533c1d70c19e0dc59e83a71ce27d"},
+    {file = "coverage-5.3.1-cp39-cp39-win32.whl", hash = "sha256:cc6f8246e74dd210d7e2b56c76ceaba1cc52b025cd75dbe96eb48791e0250e98"},
+    {file = "coverage-5.3.1-cp39-cp39-win_amd64.whl", hash = "sha256:2757fa64e11ec12220968f65d086b7a29b6583d16e9a544c889b22ba98555ef1"},
+    {file = "coverage-5.3.1-pp36-none-any.whl", hash = "sha256:723d22d324e7997a651478e9c5a3120a0ecbc9a7e94071f7e1954562a8806cf3"},
+    {file = "coverage-5.3.1-pp37-none-any.whl", hash = "sha256:c89b558f8a9a5a6f2cfc923c304d49f0ce629c3bd85cb442ca258ec20366394c"},
+    {file = "coverage-5.3.1.tar.gz", hash = "sha256:38f16b1317b8dd82df67ed5daa5f5e7c959e46579840d77a67a4ceb9cef0a50b"},
 ]
diff --git a/pyproject.toml b/pyproject.toml
index ad87347..951e662 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -9,7 +9,7 @@ license = "MIT"
 python = "^3.7"
 
 [tool.poetry.dev-dependencies]
-coverage = "5.0b1"
+coverage = "5.3.1"
 
 [build-system]
 requires = ["poetry>=0.12"]